Images are used to communicate information and ideas. Images, including print pictures, film negatives, documents and the like, are often digitized to produce a digital image that can then be instantly communicated, viewed, enhanced, modified, printed or stored. The flexibility of digital images, as well as the ability to instantly communicate digital images, has led to a rising demand for improved systems and methods for film processing and the digitization of film based images into digital images. Film based images are traditionally digitized by electronically scanning a film negative or film positive that has been conventionally developed using a wet chemical developing process.
In a traditional wet chemical developing process, the film is immersed and agitated in a series of tanks containing different processing solutions. The temperature and concentration level of the particular processing solution is strictly controlled to ensure uniformity of the development process. The film is immersed in each tank for a specific period of time depending upon the particular type of film. In particular, the development process is generally modified for film having different speeds and different manufactures.
The first tank typically contains a developing solution. The developing solution chemically reacts with the exposed silver halide to produce elemental metallic silver grains in each emulsion layer of the film. The metallic silver grains form a silver image within each emulsion layer of the film. The by-product of the chemical reaction combines with a dye coupler in each emulsion layer to create a dye cloud. The color of the dye cloud is complementary to the band of light the emulsion layer has been sensitized to. For example, the red sensitized layer typically produces a cyan dye image, the green sensitized layer a magenta dye image, and the blue sensitized layer a yellow dye image. The density of the silver image and the corresponding dye image in each emulsion layer are directly proportional to the intensity of light the film was exposed to. The developing process is generally stopped by removing the film from the developer tank and rinsing or immersing the film in water or an acidic solution.
Conventional wet chemical developing processes then removes both the silver image and the undeveloped silver halide grains from the film to produce a film negative having only a dye image within the film negative. To remove the silver image and undeveloped silver halide, the developed film is immersed and agitated in a tank of bleaching solution. The bleaching solution chemically oxidizes the metallic silver grains forming the silver image and converts the metallic silver grains into a silver halide compound. The bleached film is then immersed and agitated in a tank of fixer solution. The fixer solution removes the silver halide from the film by dissolving the silver halide crystals. The film is then washed, stabilized and dried to produce a conventional film negative.
If a digital image is required, the conventionally produced film negative is digitized using a conventional electronic scanner. Conventional electronic film scanners generally operate by directing white light through the film negative. The light interacts with the dye image and the intensity of light transmitted through the film is recorded by a sensor that produces individual red, green and blue color data. The sensor color data is used to produce the digital image.
The various processing solutions are expensive and become contaminated during the development process. These contaminated solutions form environmentally hazardous materials and various governmental regulations govern the disposal of the contaminated solutions. In addition, criminal penalties may attach to the improper disposal of the contaminated solutions. As a result, the costs associated with developing film continue to increase.
A relatively new process under development is digital film processing (DFP). DFP systems scan the film during the development process. DFP systems apply a thin coat of one or more film processing solutions to the film and then scan the film through the coating. Neither the processing solutions nor the silver compounds within the film are washed from the film. DFP systems may comprise a number of different configurations depending upon the method of film processing and the method of scanning the film. For example, in some embodiments, the metallic silver grains and silver halide are not modified and the film is scanned with visible light.